N-phenylcarbamate compounds are described in, for example, (1) Japanese Patent Laid-Open No. 146,881/1988 which corresponds to EP-A-268,989 and U.S. Pat. No. 4,831,041; (2) Japanese Patent Laid-Open No. 131,175/1989 which corresponds to EP-A-270,091 and U.S. Pat. No. 4,996,217; (3) Tetrahedron Letters, Vol. 29, No. 15, pp. 1799-1802, 1988; (4) Journal fur Praktische Chemie., 4. Reihe., Band 12. pp. 44-49, 1960; (5) Chem. Pharm. Bull., 36 (4), pp. 1305-1308 (1988); (6) INGENIERIA Y CIENCIA QUIMICA, 1979, 3 (3), pp. 132-133; (7) Japanese Patent Laid-Open No. 151,889/1975; (8) Journal of Medicinal Chemistry, 1970, Vol. 13, No. 4, pp. 713-722; etc. However, all of them fail to disclose such N-phenylcarbamate compounds as represented by the general formula (I) mentioned below according to the present invention.